A communication module allowing use of a plurality of information communication systems is shown in FIG. 12. Communication module 100 of FIG. 12 allows use of both Bluetooth system 103 having antenna 101 and wireless-local area network (W-LAN) system 104 having antenna 102. In communication module 100, a problem occurs in a case in which both systems 103 and 104 employ the same frequency band of 2.4 GHz and are simultaneously operated. When one system transmits a signal while the other system lies in a receiving state, the signal of the former system disturbs the latter system to cause extreme reduction of bit error rate (BER).
Conventional art related to the present invention is disclosed in Japanese Patent No. 3114582 or Japanese Patent Unexamined Publication No. 2001-177330, for example.
In the structure discussed above, two antennas 101 and 102 must be disposed physically separately, so that the size of a housing for storing communication module 100 consequentially increases. Two antennas 101 and 102 require two mounted positions and double manufacturing cost.